摘要: 人类白细胞抗原(Human leukocyte antigens, HLA)是人类基因组中已知多态性最高的基因家族, 为人类面对异源多变的外界生物分子所必须。以往对HLA多态性形成的研究多集中在互换式重组机制上, 文章研究了基因转换这一重要的多态性形成机制在HLA-DRB基因多态性形成中的作用。应用已知的各基因座的等位基因序列对其进行多态性分析表明, HLA-DRB是一高度多态的基因家族。用Ester Betran模型检测到32个基因转换的区域, 最小的基因转换区域长2 bp, 最远差异位点间隔为204 bp。在71~75、18~221等几个区域上出现基因转换的频数高, 成为基因转换的热点。进一步的分析显示, 71~75、205~217等热点区域分别与东方人、高加索人这两个人群密切相关, 提示基因转换的热点可能具有一定的人群特异性

Abstract: HLA is the most polymorphic gene family in human genome, which is imperative for human to face numerous heterogeneous bio-molecules. Previous studies on the formation of HLA polymorphism have been focused on gene cross-over. Here, we investigated the contribution of gene conversion, which is an important mechanism to generate polymor-phism at shaping different patterns of HLA-DRB genes. Analysis of all known HLA-DRB haplotypes and alleles demon-strated that this was a highly polymorphic gene family. Using Ester Betran’s algorithm, 32 gene conversion regions were identified. The minimal conversion tract was as short as 2 bp, and the maximum interval between two furthest SNPs was 204 bp. Moreover, gene conversion occurred more frequently in certain regions (71-75, 18-221) of various alleles, sug-gesting that these segments were conversion hotspots. Further analysis showed that the conversion regions of 71-75 and 205-217 appeared to correlate with populations of Oriental and Caucasian, respectively, indicating that conversion hotspots might be population specific.